Page Replacement Technique in python

Introduction

Page Replacement technique is used to replace page in memory frame with in os . The popular 3 approaches are

1. FIFO
2. LRU
3. Optimal

FIFO( First In First Out ) Algorithm:

1. Initialize an empty frame of size frames.
2. Set pageFault = 0 and frameCount = 0.
3. For each page in the pages list:
   • If the page is not in the frame:
   • Replace the page at frameCount with the current page.
   • Increment frameCount (modulo the frame size for circular replacement).
   • Increment pageFault.
   • If the page is already in the frame, do nothing.
4. At the end, return pageFault.

LRU( Least Recently Used ) Algorithm:

1. Initialize an empty frame of size frames.
2. Maintain a list of recently used pages.
3. Set pageFault = 0.
4. For each page in the pages list:
   • If the page is not in the frame:
     • If the frame is full, remove the least recently used page (the one at the front of the list).
     • Add the page to the frame and the end of the list.
     • Increment pageFault.
   • If the page is already in the frame:
     • Update the recently used list by moving the page to the end.
5. At the end, return pageFault.

Optimal Algorithm:

1. Initialize an empty frame of size frames.
2. Set pageFault = 0.
3. For each page in the pages list (current index i):
   • If the page is not in the frame:
     • If the frame is full, find the page that will not be used for the longest period of time:
     • Look ahead in the pages list to see when each page in the frame will next be used.
     • Replace the page with the largest index or the one not used at all.
   • Add the page to the frame.
   • Increment pageFault.
   • If the page is already in the frame, do nothing.
4. At the end, return pageFault.

Requriments

• Python
• Python environment (vs code , notepad++,anaconda,juypter notebook)

Important

The code is done using jupyter notebook so wither copy the code or run the file in jupter notebook and

Note

The code is done in python language